## Abstract A new prenylated benzopyrancarboxylic acid, **1a** (3,4‐dihydro‐5‐hydroxy‐2,7‐dimethyl‐8‐(2‐methyl‐2‐butenyl)‐ 2‐(4‐methyl‐1, 3‐pentadienyl)‐2__H__‐1‐benzopyran‐6‐carboxylic acid) was isolated from __Peperomia amplexicaulis__ and fully characterized by 1D and 2D NMR and high‐resolution
Quantum chemistry investigation of electronic structure and NMR spectral characteristics for fluorides of dialkylamidosulfoxylic acids and related compounds
✍ Scribed by A. B. Rozhenko; W. W. Schoeller; V. N. Kozel; V. E. Pashinnik; Yu. G. Shermolovich
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 370 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0749-1581
- DOI
- 10.1002/mrc.2466
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The parent (H~2~NSF) and N,N‐dialkyl‐substituted fluorides of amidosulfoxylic acid (R~2~NSF, RMe or R~2~NMorph) as well as the related compounds XSF (XCH~3~, OH, F, SiH~3~, PH~2~, SH, Cl) have been investigated with quantum chemical calculations at the ab initio (MP2) level of approximation. The geometries, electronic structures, molecular orbital (MO) energies and NMR chemical shift values have been calculated to evaluate the role and extent of the polarization and delocalization effects in forming of the high‐field fluorine NMR resonances within the series of interest. The δF magnitudes for all investigated fluorides of amidosulfoxylic acid as well as the δN value calculated for Me~2~NSF are in the good agreement with the ^19^F and ^14^N NMR chemical shift values measured experimentally. For the parent compounds, H~2~NSF and H~2~NSO~2~F, the orientation of principal axes of the magnetic shielding tensors and the corresponding principal σ~ii~ values along these axes have been qualitatively interpreted basing on the analysis of the MO interactions in the presence of the rotating magnetic field. Copyright © 2009 John Wiley & Sons, Ltd.
📜 SIMILAR VOLUMES
## Abstract The structure of 3β‐hydroxyballotinone, a new labdane diterpenoid isolated from __Ballota undulata__, has been established by NMR spectroscopic studies. In addition, complete and unambiguous assignments of the ^1^H and ^13^C NMR spectra of three other already known labdanes (ballotinone